1. Field of the Invention
This invention relates to a molten metal heating method for heating a high temperature molten metal like molten steel held in a container. The molten metal heating method according to this invention is applicable to heating and temperature control for a molten metal held in a tundish of a continuous casting.
2. Discussion of the Prior Art
In a foundry, a molten melting is held and reserved in a container until it is processed in the next process. And there is a problem that the molten metal cools down in the container. In a continuous casting, for instance, the molten metal is held in a tundish before pouring it in a water-cooled mold, and the molten metal cannot help being cooled down in the tundish.
Accordingly, electrodes are immersed into the molten metal in the container to maintain the molten metal at a predetermined temperature, whereby an electric current is flowed in the molten metal and Joule heat is evolved to heat the molten metal directly. Further, the following heating method has been known, i.e. the molten metal in the container is heated by an induction heater, or by a plasma heater in which a plasma torch is disposed over the container.
However, the heating method using the electrodes, in which the molten metal is heated by the Joule heat evolved by the electric current flowing in the molten metal, requires a very large electric current, because the molten metal has a very small electrical resistivity. In addition, it is necessary to provide special equipment like the induction heater or the plasma heater when employing the induction heating method or the plasma heating method.